Colleges need effective universal prevention strategies to reach the substantial number of students who may be at risk for alcohol misuse and related harm. To address this need, Outside The Classroom developed a 2- 3 hour online course known as AlcoholEdu for college freshmen. Approximately 140 colleges are now mandating AlcoholEdu for their incoming freshmen despite the lack of research on its effectiveness. AlcoholEdu incorporates features of effective (Tier 1) intervention strategies recommended by the NIAAA Task Force on College Drinking. The proposed study will be the first to use a multi-campus experimental design to determine whether AlcoholEdu has beneficial and sustained effects on alcohol use and related harm among freshmen classes. We are proposing a randomized controlled study that will include 30 colleges. Fifteen of the colleges will be randomly assigned to implement AlcoholEdu for two consecutive freshmen classes in Fall 2008 and Fall 2009. Colleges that serve as controls in the 2008-09 academic year will also implement AlcoholEdu in the fall of 2009. Repeated cross-sectional surveys of freshmen classes in fall and spring semesters and two surveys of sophomore classes will allow us to examine both short-term and sustained AlcoholEdu effects. The specific aims of this study are: (1) To determine whether and to what extent AlcoholEdu reduces both immediate and longer-term alcohol misuse and related problems in the freshmen student population;(2) To determine if any observed effects of AlcEdu on alcohol misuse and related problems in the freshman student population are stronger if the program was also administered to the prior class of freshmen in the previous year;and (3) To assess the mediating effects on alcohol misuse and related problems of student-level psychosocial factors (e.g., normative beliefs, alcohol expectancies) targeted by AlcoholEdu. Mediating effects of sophomore class levels of alcohol use and related problems also will be examined for the 2009-10 freshmen class. Secondary aims of the study are to examine possible differences in AlcoholEdu's effects for colleges with (a) relatively high vs. low levels of student participation in the program, and (b) relatively high vs. low rates of baseline heavy alcohol use among incoming freshmen classes. We will also examine the possible combined effects of AlcoholEdu and other campus-wide prevention programs (e.g., social norming campaign) if there are enough colleges implementing AlcoholEdu with other campus-wide programs. Findings of this study will be of theoretical importance as no prior experimental studies have examined population-level effects of a web-based prevention program for college students that is based on social-cognitive theories of health behavior at the individual level. This study will also help college practitioners and administrators make an informed decision about whether to include AlcoholEdu as part of a comprehensive alcohol misuse and harm prevention strategy.